HIIT: How to edit sets?

Hi,

I'm a bit puzzled why I cannot add sets in my HIIT activities... I recorded a multisport one (HIIT - Strength - HIIT), on the first leg I cannot edit it at all

First leg:

As you can see, no edit buttons or buttons to add sets whatsoever.

Third leg:

the buttons are there.

I'd really like to add the exercises to the first part, but ... am I missing something somewhere?

(Note: I've never been able to add exercises to a HIIT if it's only "one" recorded activity.)

Sorry, I just noticed I posted this in the wrong category :(